Dam



C. V. DAVIS DAM Filed Feb. 26, 1934 ATTORNEY Patented Jan. 2S, 1936 DAM Calvin V. Davis, Mount Vernon, N. Y., assignor to Ambursen Construction Company, Inc., New York, N. Y., a corporation of New York Application February 26, 1934, serial No. 712,868

5 Claims.

This invention relates to a novel and improved dam, the novel features of which will be best understood from theV following description and the annexed drawing, in which I have sho'wn a selected embodiment of the invention, and in which:

Fig. 1 is a vertical sectional view on a plane extending up-stream and down-stream, and showing one form which the invention may take.

Fig. 2 is a section on the line 2 2 of Fig. 1.

This invention relates to a form of dam sometimes referred to as the Ambursen type or, in other words, to a hollow dam, in which there is provided an inclined up-stream water-bearing deck supported by a plurality of buttresses extending down-stream from the deck. In the design of this type o'f dam, particularly on soft foundation material, it is sometimes difficult to provide the proper amount of safety against sliding on the foundation material, and the difliculty is increased by the seepage of water under Y the dam which almost invariably takes place in any type of dam.

It has been common practice to make the slope of the deck a flat one, in order to increase the amount of water bearing thereon and thus increase the weight exerted on'the foundation. Of course, this arrangement will help resist sliding, but at the same time it necessitates agreater amount of material in the deck and also in the buttresses, the buttresses not only being longer to take care of the longer deck, but also being made with more material td withstand the additional weight placed thereon by the additional volume of water. Moreover, the arrangement being discussed results in an unfavorable distribution of principal stresses in the dam structure, particularly in the buttresses. This is particularly true with the second principal stresses which should be in compression, but are actually apt to bein tension when following the prior art practice. The result is the necessity for use of steel reinforcement, particularly near the deck where its presence is undesirable.

According to' this invention, I provide an inclined up-stream water-bearing deck I supported on buttresses 2, the down-stream edges of which may be joined by a wall 3, although this is not essential. It will be noted that the deck l is provided with a slope which is steep as compared with generally accepted practice in this type of dam, particularly when the foundation material 4 is soft. This steepness of the deck slope makes it possible to decrease the material in the buttresses 2, both by decreasing the up-stream and down-stream length thereof, and also by decreasing the amount of water carried by the deck and thereby making it possible to' decrease the weight of the buttresses because of the relatively light load carried thereby.

Extending up-stream from the lower edge 5 of the deck is a slab 6 resting directly upon the foundation material 4 and preferably connected to the deck by a suitable expansion joint l. The

dam is provided with a suitable cut-off wall 8,

here shown as extending downwardly from the up-stream edge of the slab 6. Any water which seeps by or through the slab or cut-off wall may be collected in gravel pockets 9 and conducted by drains I0 into the spaces between buttresses. The slab 8 is also preferably tied securely to the buttresses as by steel reinforcement II.

By the above arrangement alone, the cost of the dam is materially reduced because of the great economy in material, for reasons fully described above. At the same time, it will be seen that the sliding tendency of the dam is greatly reduced because of the weight of water acting upon the slab 6, but since this slab is resting directly upon the foundation material, no superstructure to support the same is required. Similarly, the slope of the deck is such that the stresses in the dam are substantially all in compression, thus eliminating the necessity for :reinforcing steel.

I have also shown a feature which may be used. either alone or in connection with the slab 6 for decreasing the tendency for the dam to slide on the foundation material. Extending transversely into the buttresses and preferably connecting them, I provide a foundation I2 which is preferably arranged in one or more steps as indicated, with the rear edge I3 of each step lower than the front edge I4 thereof. On the rearmost step, the rear edge isl connected to the lower edge of the deck or to the slab, in this case a suitable joint I5 being indicated. The steps are preferably arranged substantially normal to the resultant forces acting in the buttresses and which may be represented by the arrows R1 and R2. By this arrangement, the resistance to sliding is greatly increased, the tendency to slide being resisted, for example, by the material above the lines I5 and I6 acting, respectively, on the two steps of the foundation. It will be seen that the rear edge of the front step is higher than the rear edge of the next up-stream step, so that a line I1 connecting them is inclined upwardly in a downstream direction. This means that the general sliding movement of this dam would be along the upwardly inclined plane in which this line is disposed and therefore, of course, the tendency to slide is further diminished by the weight of the dam.

In order to avoid the building up of an uplift pressure caused by the percolation or seepage of Water under the dam, the drains III have been provided, and I also provide drains I8 through the foundation I2. Water may then pass freely upwardly and run off in the space between buttresses, suitable drains I9 being provided through the down-stream wall 3, if such wall is used. f- Drains 2D may also be provided passing throughA the buttresses 2.

As a'further feature of economy and'safety, cross walls 2| may be provided extending between and connecting adjacentv buttresses 2 and also connected to the foundation I2. These cross walls not only serve to stiffen and strengthen the superstructure asa Whole, but also furnish an additional support for the foundation. For example, considering the foundation up-stream from one of the cross walls 2 I, it will be seen that this portion of the foundation has a four-way support in that it is supported on eithervside by adjacent buttresses and is supported at its downstream edge by the cross wall and at its upstream edge by the slab 6. When the cross walls 2| are used, suitable drains 22 may be provided therethrough, so that water discharged from the drains I0 and I8 may find its way to the drains I9.

While I have shown the invention as embodied in a specific form, it is to be understood that various changes in details may be made without departing from the scope of the invention, and I therefore do not intend to limit myself except by the appended claims.

I claim:

1'. A dam comprising an inclined up-stream water-bearing deck supported by a plurality of spacedbuttresses extending downstream therefrom, and masonry foundations for said buttresses extending transversely thereof, said foundations having one or more steps, vwith the upstream edge of a step disposed lower than the down-stream edge thereof.

2. A dam comprising an inclined up-stream water-bearing deck supported by a plurality of spaced buttresses extending down-stream therefrom, and masonry foundations for said buttresses extending transversely thereof and substantially closing the spaces between adjacent buttresses, said foundations having one or more steps, with the up-stream edge of a step disposed lower than the down-stream edge thereof.

3. A dam comprising an inclined Yup-stream water-bearing deck supported by a plurality of spaced buttresses extending down-stream therefrom, masonry foundations for said buttresses extending transversely thereof, said foundations having one or more steps, with the up-stream edge of a step disposed lower than the down-stream edge-thereof, and bracing members extending between adjacent buttresses and connected to said foundation.

4. A dam comprising an inclined up-stream water-bearing deck supported by a plurality of spaced buttresses extending down-stream therefrom, masonry foundations for said buttresses extending transversely thereof, said foundations having one or more steps, with the up-stream edge of a step disposed lower than the downstream edge thereof, and'bracingv members extending between adjacent buttresses and connected to said foundation at the down-stream edges of said steps. J

5. A dam comprising an inclined up-stream water-bearing deck supported by a plurality of spaced buttresses extending-down-stream there- 

